Sleep significantly impacts quality of life of an individual. The human sleep cycle generally conforms to a circadian rhythm that is regulated by a biological clock. Regular periods of sleep enable the body and mind to rejuvenate and rebuild. Normal sleep is characterized by a general decrease in metabolic rate, body temperature, blood pressure, breathing rate, heart rate, and other physiological functions. Normally a person alternates between a rapid eye movement (REM) sleep stage and a non-REM (NREM) sleep stage in approximately 90 minute cycles throughout a time period of sleep. A typical eight hour period of sleep may comprise a five-step sleep cycle identifiable through electroencephalogram (EEG) brain wave activity.
Lack of sleep or decreased sleep quality may result in health problems, such as depression or anxiety. In order to improve the quality of sleep, sensors are typically used to detect brain wave activity of a person and to determine the stages of sleep the person cycles through. The person can then use such information to identify factors causing lower sleep quality and to modify his habits to improve sleep quality. However, attaching a sensor that detects brain waves is often difficult to maintain attached to the forehead because of the typical movement a person undergoes during sleep.
FIG. 1 (Prior Art) is a perspective diagram of a front view of a conventional physiological sensor apparatus 1 for detecting brain wave activity of a user. The physiological sensor apparatus 1 uses a headband 2 to secure physiological sensor 3 to a forehead of the user. FIG. 2 (Prior Art) is a perspective diagram of a back view of the conventional physiological sensor apparatus 1. FIG. 3 (Prior Art) is a perspective diagram showing how the conventional physiological sensor apparatus 1 is displaced from the user's forehead during a period of sleep. Reference numeral 4 identifies a displacement of the sensor 2 away from the forehead due to a user moving during sleep. Because the sensor 2 often becomes displaced or removed during the night, the obtained brain wave activity information is often inaccurate or incomplete. A solution that overcomes these challenges is desired.